A butterfly valve means that the closing member (valve or butterfly plate) is a disk, which rotates around the valve shaft to open and close a valve. The valve mainly serves to cut off and throttling. Butterfly valve opening and closing device is a disc-shaped butterfly plate, rotating around its own axis in the valve body, so as to achieve the purpose of opening and closing or adjusting. The butterfly valve is suitable for conveying various corrosive and non-corrosive fluid media in engineering systems such as furnace, gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting and power generation environmental protection, etc., for regulation and truncation. The flow of media. Butterfly valves are classified into: handle butterfly valves, turbine butterfly valves, pneumatic butterfly valves, and electric butterfly valves.